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Author Topic: 4th axis - GCode degrees vs distance  (Read 19856 times)

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Offline Vogavt

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Re: 4th axis - GCode degrees vs distance
« Reply #20 on: January 25, 2011, 10:38:38 AM »
Resurrecting an old thread here. After reading through this I still need to get my mind around what it takes to work in the A-axis. I would ask that someone clarify my understanding.

Example One: If you are wanting to engrave a cylinder you could to set all the A-axis references in the gcode to Y-axis and simply tell Mach the diameter of the cylinder somewhere. My question is now I'm not sure how having the A-axis in angular or linear would then apply or even how to calibrate the steps per.

Example Two: If I'm wanting to drill four holes at 900 apart, I'd need to tell Mach that I'm wanting an angular setup and reference A-axis in degrees. Correct?

Example Three: To add even more confusion, how do I cut threads?

Still not clear on how to make the A-axis move at a reasonable rate when the other axes are moving.

I suppose I can see where I might need different profiles.


Could someone post a simplified explanation of how to set this up in Mach and where/what it applies to? I've read several posts now and like others have said "I'm more confused now than ever".

Thanks in advance,
Vogavt

Offline RICH

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Re: 4th axis - GCode degrees vs distance
« Reply #21 on: January 25, 2011, 12:04:54 PM »
Vogavt,
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Example One:
Spend $20 and buy a program called Wrapper as it will do all the converting for you and save you from mistakes.

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Example Two:
Yes, the rotary is set up as Angular, then the code is sort of like:

G*********  ( DRILL HOLE  / CANNNED CYCLE)
G0 A90 ( ROTATES THE A AXIS 90 DEGREES )
Repeat above if in Incremental mode



Have a look in the Tool Box as there is a canned drill cycle for the lathe which can generate all the code.
There is a read me file in the file explaining how to install and use.

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Example Three:
In another thread there was a suggestion, but, I would recommend going back to using the lathe with a conventional motor
using an index. See Threading on the Lathe in Members Docs.

You need a seperate profiles for rotary  when using it as Rotary  or linear or for that matter slaving it.

RICH

Offline Vogavt

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Re: 4th axis - GCode degrees vs distance
« Reply #22 on: January 25, 2011, 01:02:12 PM »
I did purchase CNCWrapper a couple of months ago. Great program but it doesn't allow Arc commands due to Mach limitations. All arcs must be converted to lines.

When I asked him about it he gave a good explanation as to why it wouldn't. Can remember the details, but it was Mach related, not his software.

Offline RICH

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Re: 4th axis - GCode degrees vs distance
« Reply #23 on: January 25, 2011, 05:24:08 PM »
From the code i have seem it generates it breaks the arc into line segments as you so state.
For some things that may be fine, but maybe not for some forms of engraving. When you manually engrave something around a cylinder and are chasing
your cutting small straight lines , just a matter of how small they are. Not true if your hand engraving and using an engraving ball.
Must admit that i have not used Wrapper to any great extent so can't really find fault with it nor tried enough parameters to judge results against non linear moves.

My hand engraving days are long gone and only have fond memories when Remington Arms was developing their machine to try to duplicate hand engraving.
I was more interested in learning and watching the pro's work away in the custom shop. ;)

RICH